1. Field of the Invention
Human powered watercraft such as surfboards, skim-boards, body boards, boogey-boards, and the like are for thrill seeking wave riders. Unfortunately, in addition to being underpowered due to inefficient harnessing of the human engine many of these products suffer from ungainliness, fragility, difficulty of use, and high cost, limiting their acceptance in the market. Therefore, a new human powered watercraft is needed as is a new human power propulsion system for such craft to enhance oceanic and fresh-water athletic pursuits and reduce the cost and complexities thereof and so make more available to all the joys of the life aquatic.
Within the above field of art, surfing continues to enjoy high popularity but, it is well understood, standard paddling methods (prone and knee-paddling) yield a top speed of at best 5 MPH and that speed only for short durations; in general most surfers cannot paddle for longer than 15 minutes without some rest. What is more, the surfer is unable to propel from a standing position and is also statically unstable while standing upon an unmoving surfboard or other water board. While in conditions of large surf, intrepid surfers attempting to paddle out often spend all of their physical reserves trying to make headway against seemingly endless wave trains and white water combers. The surfer that does make it out to the line-up will be depleted and need rest. Only then will he or she be able to summon the arm power needed to pull into a large breaking wave. Unfortunately, the surfer so fatigued is more likely to make costly errors, often endangering him self and other surfers nearby. Consequently, a new means of propelling the surfer which harnesses more power from the human engine will make easier the catching of waves, the transit from beach to wave and will not only enable more waves to be ridden but will enable the use of the surfboard so outfitted as a transportation vehicle from break-to-break and from beach-to-beach at speeds approaching and beyond 10 MPH. A new human powered watercraft and propulsion system will be of particular interest to life guards, divers, surfers, body-boarders, and skim-boarders.
2. Description of the Prior Art
Maisonneuve, U.S. Pat. No. 4,464,126, propels a surfboard by thrusting a lever forward and aft from a sitting position to drive a lower fin up and down. The system does not allow the surfer to move about the surfboard and the lower keel structure causes yaw instability with forward motion.
Chen, U.S. Pat. No. 6,468,118 propels a surfboard thru two foot treadles with an up and down leg motion deflecting separate fins. This system attaches the user to the board which can be dangerous when the board rolls over, somewhat entrapping the user.
Momot, U.S. Pat. No. 4,968,273 propels a surfboard with a single treadle driven fin using weight shifting forward and aft to propel the board. The system has a great deal of drag surface offered to the water, does not stow and so is constantly dragging down board speed.
Domancic, U.S. Pat. No. 5,549,491 propels a surfboard or boat by a single treadle driving two fins by a lateral, side to side weight shift. This motion is particularly destabilizing to a surfboard rider as the board is narrow and least stable laterally.
Malm, U.S. Pat. No. 3,377,977 propels a surfboard by a sculling-sweeping motion of a centrally pivoted oar. The lateral side to side motion of this system destabilizes the surfboard.
Ueno, U.S. Pat. No. 4,936,802 propels a surfboard by a single foot treadle driving a vertical fin to sweep laterally back and forth. The fin motion causes the boat or board to slough sideward without the stabilizing presence of a keel.
Ketterman, U.S. Pat. No. 6,022,249 propels a kayak via foot treadles that drive two flexible fins in opposing directions about the keel of the boat. The system is heavy and complex while also being subject to damage during beaching of the vessel as the fins are most exposed below the keel and users frequently forget to stow the system.
Puzey U.S. Pat. No. 6,099,369 propels a tricycle hydrofoil by a bounding up and down motion of the user. The system suffers from the inability to start from the water and is unstable in yaw when in following seas.
Heywood U.S. Pat. No. 5,127,855 propels a boat from a bicycle mounted atop the vessel. This and all other bicycle systems suffer from the fatal flaw of needing to entrap the users' feet (clip-in) in order to maximize power output. Being clipped into the propulsion system makes emergency exit from the vessel very difficult and potentially fatal.
Triantaffyllou U.S. Pat. No. 5,740,750 propels a fish-like submersible via arm and leg motion of two tandem divers. Emergency egress is quite difficult since the users are encased within the system. The system is designed for stealth as opposed to recreational surfing.
Shiraki U.S. Pat. No. 5,194,024 propels a surfboard via a pedal-crank propeller system operated by a recumbent seated rider. This and all recumbent systems impede the operators ability to react to perturbing waves by limiting all but the users head from counteraction. As with other pedal and crank systems, the device is most efficient when one is clipped in and as stated previously, this makes emergency egress problematic and potentially fatal.
Gander U.S. Pat. No. 4,304,555 propels a float device by a foot operated bell crank driven fish-fin. Absent a keel, the vehicle is unstable in yaw when propelled thusly.
Gaudin U.S. Pat. No. 4,872,861 propels a surfboard via a hand operated bell crank driven fish fin. The system suffers from lack of power common to all arm powered systems.
Stoms U.S. Pat. No. 621,465 propels a boat via a bicycle system.
Whiting U.S. Pat. No. 2,195,527 is a tri-segmented float propulsion system which suffers from general instability.
Han U.S. Pat. No. 6,033,276 propels a surfboard via a bell crank foot operated fish fin. The system causes the board to yaw during operation.
Merrill U.S. patent Ser. No. 1,186,413 propels a floatation body by foot operated treadle driven propeller and maintains pitch attitude via hand controlled elevator fins. The system suffered from excessive drag caused by the users' legs projecting into the water during propulsion.
Newby U.S. Pat. No. 1,324,687 propels a floatation device via propeller driven by a vertical lever under the forward and aft urging of the user. The system is heavy, underpowered, and unstable in pitch when powered thusly.
Skitsko U.S. Pat. No. 3,718,109 propels a sloughing body by forward aft or lateral body motions. The system is slow due to excessive surface area in the water and is unstable.
Proverbio U.S. Pat. No. 5,816,871 propels similarly to Whiting and suffers according to the same deficiencies.
Cleary 20060042536 attempts to propel and steer a kayak via a strut hydrofoil. The strut hydrofoil is rotate-able about a strut axis which axis is tilt able without constraint within a cone of 15 degrees from normal to the surface of the water This relative freedom from-restraint of the strut hydrofoil system when combined with varying sea conditions often causes even the most experienced user to fall off the vehicle while at the same time causing local structural degradation of the strut and vehicle. Neither the strut nor the hydrofoil are able to be stowed within the body of the kayak and so are subject to impingement and damage by unseen objects in the water primarily and then due to secondary impact by the user. The strut-hydrofoil system described is unsuited to ocean-wave riding vehicles particularly surfboards, skim boards and the like as they operate in shallow waters and are therefore subject to frequent impingement with the submarine terrain.